Sporadic Firing...PCM or IDM Issues? - Ford Powerstroke Diesel Forum
 
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post #1 of 6 Old 06-14-2019, 05:30 AM Thread Starter
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Sporadic Firing...PCM or IDM Issues?

Hey Everyone,

A couple of weeks back my truck started firing a little weird. It wasn't misfiring, more that it was actually hitting harder on a certain cylinder, than it was on the other cylinders, but it was completely random. The best way I can describe it is kind of like when a points distributor gets water under it. Anyways, it wasn't that big of a deal, and it seemed to straighten out.

Well now a couple weeks later (yesterday), it was running like absolute crap. When I first started it in the morning, RPMs took ran up to like 1,000 rpm instead of its normal idle, and then it started running a little rough. On the way to work, it was lurching, and was trying to die on me sometimes at stop lights. When I got to work, I checked my VC plugs and my IPR plug to make sure everything was plugged in, and that "seemed" to fix it, but I think it was pure coincidence.

Today, I drove it to the plant that I normally work at (35 miles) and it was intermittently lurching. Sometimes it'd do it under light acceleration and it'd straighten out, then other times it'd randomly do it when cruising along. When I'm under light acceleration, I can hear my injectors change tone as if I switched my chip from my stock tune to my extreme tune (but I'm not changing anything). This may only be coincidence, but my radio also didn't turn at all (completely dead) during my 35 mile drive in this morning. Once I got to work, I shut it off and fired it right back up, and my radio kicked on no issues. It threw a CEL about halfway through the drive, but it cleared as soon as I shut the truck off.

Has anyone had similar symptoms? I'm thinking that I'll get it home this evening and pull my chip to see if that makes a difference, but after that I'm at a bit of a loss of diagnostics. Thanks for the help!
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post #2 of 6 Old 06-14-2019, 10:04 AM
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I was going to mention physically pulling the chip and see what happens. If you can, I would read the codes that may have been stored. Check the ICP connector for oil and the IPR solenoid nut for snugness. Cheers!
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post #3 of 6 Old 06-14-2019, 01:06 PM Thread Starter
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Welp, ran out to the truck really quick, pulled the chip and fired it up... Ran like junk still. I've still yet to head home, so I'll see how it does on the drive back (without the chip), but I'm kind of trying to figure out next steps.

I'm thinking next I'll check to verify the resistances on my UVCH and injector circuits. Resistance on the injector circuit should be about 2.5 to 3.5 ohms correct?
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post #4 of 6 Old 06-14-2019, 07:21 PM
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Yes about 3 ohms. Of course, there should be no continuity (open circuit) between the 2 outside pins and any of the 3 inner pins on each connector). Cheers!
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post #5 of 6 Old 06-14-2019, 08:16 PM
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Sounds like an ICP issue but a CPS can also cause similar issues.

For now unplug the ICP connector and check for oil in there.

Then check the IDM, shake it to see if water made it in.

Then your best bet is a scanner for the code and read live data. You can change the CPS but the injectors changing tone do seem to point towards an HPOP issues relating to the ICP or IPR.
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post #6 of 6 Old 06-15-2019, 03:41 PM Thread Starter
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I think I found it! Or at least I've got a pretty good smoking gun.

I got ready to check my injector circuits but decided to fire the truck up and do the wiggle stuff one more time. Tried all my individual injector harnesses, and the CPS, and got nothing. Then I wiggled the main injector harness and got a response. Started digging, and found an exposed wire that was grounding out on the driver's side lifting eyelet. Sealed it, taped, and tried to relocate it as best as possible.

Thanks for all of the help! The experts on this forum has saved me more times than I can count. I'll give an update after I've put some miles on it.
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